Green biosynthesis of gold nanometre scale plates using the leaf extracts from an indigenous Australian plant Eucalyptus macrocarpa

Abstract

In this preliminary study, we demonstrate an environmentally friendly process for the green synthesis of gold nanometre scale particles using the leaf extract from an indigenous Australian plant Eucalyptus macrocarpa as both the stabilising agent and the reducing agent. The synthesis process is straightforward, clean and non-toxic. It also has the advantages of being performed at room temperature and does not need complex processing equipment. Formation of the gold nanometre sized particles was confirmed and characterised by UV-visible spectroscopy, X-ray diffraction, transmission electron microscopy and field emission scanning electron microscopy. The antibacterial activity of the synthesised gold particles was also quantified using the sensitivity method of Kirby-Bauer.

Biosynthesis of silver nanoparticles using indigenous Xanthorrhoea glauca leaf extract and their antibacterial activity against Escherichia coli and Staphylococcus epidermis

“…Previous studies report the brown colour indicates the formation of Ag nanoparticles in the reaction mixture due to excitation of surface plasmon vibrations as seen in Figure 1b. 24,26 Mie"s theory predicts a single intense SPR peak in the absorption spectra for spherical metal nanoparticles. However, the broad peak centred at 440 nm in this study was due to the anisotropic nature of the nanoparticles.…”

“…Biological synthesis was adopted since previous studies by the authors on other Australian indigenous plants have shown that the leaf extracts can act as both reducing agent and stabilizing agent during the synthesis process. 24 Also, the aqueous based technique is straightforward, eco-friendly and produces no toxic waste products.…”

Biogenic synthesis of silver nanoparticles from waste banana plant stems and their antibacterial activity against Escherichia coli and Staphylococcus Epidermis

“…Therefore, to avoid the disadvantages associated with traditional manufacturing processes new green chemistrybased procedures using biological entities such as bacteria, fungi, yeast, and plant extracts are currently under investigation. [18][19][20][21] Among the alternatives, the use of plant extracts offers a straight-forward, clean and eco-friendly method of producing noble nanoparticles such as Au and Ag. 22,23 However, very little research has been done investigating the possible utilization of naturally occurring agricultural plant wastes for the biogenic synthesis of Ag nanoparticles.…”

Nanoparticles and Their Toxicology Studies: A Green Chemistry Approach

“…Unfortunately, size reduction also tends to introduce surface imperfections that can significantly impact the overall physicochemical properties of the fabricated nano particle. The second, bottom up approach builds nanoparticles via the assembly of atoms, molecules, and smaller particles or monomers [11]. Unfortunately, many of the chemical and physical processes used in both approaches suffer from several drawbacks such as low material conversion rates, are technically complex, have high energy requirements, and are generally expensive.…”